Production of SiOC-bonded polyether siloxanes

ABSTRACT

SiOC-bonded polyether siloxanes are produced by transesterification of alkoxysiloxanes with polyetherols in the presence of trifluoromethanesulfonate as catalyst. The computational total water content of the reactants including alkoxysiloxanes and polyetherols is ≤5000 ppm by mass, advantageously ≤300 ppm by mass, preferably ≤150 ppm by mass, more preferably ≤100 ppm by mass, in particular ≤50 ppm by mass. The determination of the individual water contents is performed beforehand, preferably by titration according to Karl Fischer.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit to European application EP19176883.7, filed on May 28, 2019, the content of which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention is in the field of polyether siloxanes. In particular, itrelates to a process for producing SiOC-bonded polyether siloxanes fromalkoxypolysiloxanes by transesterification with polyetherols.

Discussion of the Background

SiOC-bonded polyether siloxanes are known constituents of defoamerswhich show particular efficacy and stability for defoaming aqueous andnonaqueous media. This includes not only foam inhibition, defoaming andvery good storage stability but also excellent compatibility in aqueousand nonaqueous media. All of these properties are very important formodem paint applications.

In the present case the term “defoamer” comprises not only products andformulations which prevent foam but also those which destroy foam orallow deaeration. In practice the boundaries between these products arefluid and the common umbrella term defoamer is therefore used here.

In many industrial processes, particularly when employing aqueous media,it is necessary to inhibit or even entirely prevent the undesiredformation of foam during production or processing steps since foam orfroth layers which accumulate during stirring and dispersing operationsor collect in the containers during the filling procedure can prolongproduction times or else reduce the effective volume of the plant/evenprevent correct operation thereof (overflow, lack of color transfer).

This is achievable by adding defoamers which even at very low usageconcentrations from about 0.001% by weight are capable of avoiding ordestroying undesired foams without bringing about any surface defectsafter application of the systems. In practice this latter factor is atleast as important as good defoaming.

Surface defects are to be understood as meaning characteristicsundesired by the user such as for example pinholes, craters, glossreduction, orange peel effect, wrinkle formation and loss of adhesion inthe coating system. However, a corresponding long-term stability of theformulation is also very important for the user since products such aspaints are often not used immediately but sometimes only after arelatively lengthy period of storage. If stored under extreme climaticconditions (heat and incident sunlight) the efficacy of a defoamerformulation can sometimes collapse after only a short time.

The synthesis of polyether siloxanes is carried out by the joining of apolyether to a polysiloxane chain via an Si—OC or Si—C bond. At thispoint the chemistry provides numerous options of different polyethersiloxane structures. Accordingly, not only linear structures subdividedinto two subclasses—the A-B-A triblock copolymer structures and theA-(B-A)x and C-A-(B-A)x-C1 multi-block copolymer structures—but alsoslightly or strongly branched copolymer structures and comb-likecopolymers may be synthesized.

Those skilled in the art are aware that these SiOC-bonded polyethersiloxanes are a product class that does not tend to resinify. Even ifSiOC-bonded polyether siloxanes comprise reactive groups, such as forinstance hydroxyl groups, they are not used for intentionalcrosslinking. In contrast to silicone resins they are not film-forming.

Numerous transesterification processes are known from the related art.For example, WO2011/060050 A1 concerns a coating system consisting of abinder and particles, wherein the use of particular siloxane-basedmodifying agents is of central importance. A route to these modifyingagents is provided by dehydrogenative coupling of SiH-bearing siloxaneswith polyalkylene glycol monoalkyl ethers in which zinc acetylacetonatefunctions as a catalyst.

WO2015/039837 A1 claims a hydroxyl-containingsilicone-polyester-acrylate binder and the production and use thereof.It is elucidated therein that inter alia zinc acetylacetonate is acatalyst which in the presence of moisture promotes the hydrolysis andcondensation of silyltrialkoxy groups and thus brings about the curingof the system even at room temperature. Similarly, EP 2636696 A1 toorecites zinc acetylacetonate as a suitable hydrolysis and condensationcatalyst for curing modified alkoxylation products comprising anon-terminal alkoxysilyl group and a plurality of urethane groups.

Transesterification processes on alkoxyorganosilicon compounds, runeither batchwise or continuously, are typically catalysed by addition ofacids or bases, as disclosed for example in U.S. Pat. No. 6,489,500 B2.

Older patent documents such as U.S. Pat. Nos. 2,917,480 and 2,834,748recite organic acids such as monochloroacetic acid, perfluoroacetic acidor else alkaline compounds such as potassium silane oxide as catalyststo be used.

Apart from the use of pure acids or bases and devoted to the objectiveof providing an improved process for the transesterification ofalkoxysilicone compounds, U.S. Pat. No. 3,133,111 in this connectiondiscloses as catalyst the salt-like combination consisting of the simplealiphatic acids having 1 to 7 carbon atoms or of the chlorinated acidsderived therefrom or else in particular from the perfluorinated acidsderived therefrom with a basic component which comprises the alkalimetal hydroxides of the alkali metals whose atomic number is greaterthan 11 and also ammonium hydroxide, quaternary alkylammoniumhydroxides, nitrogen-containing organic bases, with the proviso that theacid represented in the salt combination is present insuperstoichiometric concentration.

U.S. Pat. No. 3,801,616 concerns the production of SiOC-based liquidsiloxane polyoxyalkylene block copolymers by transesterificationreactions between alkoxy-comprising siloxanes and polyoxyalkyleneshaving at least one alcoholic function each in the presence of salt-likecatalysts having a defined water solubility and a pH window defined inaqueous solution.

In the production of thermally curable silicone resins for use aselectrical insulation material, U.S. Pat. No. 4,408,031 recites astransesterification catalysts titanate esters, cobalt salts of organicacids or organic acids or sulfonic acids, such as preferablypara-toluenesulfonic acid or benzenesulfonic acid.

In addition to the previously mentioned alkyl titanates, for examplebutyl titanate, EP 1136494 A2 also recites tin compounds such asdibutyltin dilaurate.

It must further be noted that the transesterification reaction on ahighly crosslinked silicone resin is a technically low hurdle since,even in the case of an unfortunate selection of a catalyst recited inthe related art, side reactions such as undesired equilibration orskeletal rearrangement do not occur.

A much higher technical hurdle by contrast is that of reproducibly cleanproduction of SiOC-bonded polyether siloxanes by transesterification ofalkoxysiloxanes with polyetherols, particularly when the target productsare inputs for very demanding applications as surface-active substances.High, if not quantitative, conversions are mandatory here in order toreliably establish the particular effect.

Zinc acetylacetonate Zn(acac)₂ is known as a catalyst for numerousreactions.

EP 34 38 158 A1 discloses a process for producing SiOC-bonded polyethersiloxanes by transesterification of alkoxysilanes with polyetherols inthe presence of zinc acetylacetonate as a catalyst. This process has theadvantage that it no longer requires the use of acids or bases which inindustrial practice necessitate elevated safety measures in theirhandling but also in the choice of suitable vessel materials.

However, it has been found that the process according to EP 34 38 158 A1forms hexamethylcyclotrisiloxane (D3) as a by-product. D3 has apropensity for being deposited on the production conduits and thuscauses servicing and maintenance costs.

It is therefore desirable to provide a process which does not have theabovementioned disadvantages.

It has now been found that, surprisingly, on the basis of the processaccording to EP 34 38 158 A1, trifluoromethanesulfonate is in factsuitable as a particularly excellent catalyst for thetransesterification of alkoxysiloxanes with polyetherols and thus forthe production of chemically complex systems; in particular theformation of hexamethylcyclotrisiloxanes can be at least minimized orsignificantly reduced.

SUMMARY OF THE INVENTION

The present invention includes the following embodiments.

1.) Process for producing SiOC-bonded polyether siloxanes bytransesterification of alkoxysiloxanes with polyetherols in the presenceof trifluoromethanesulfonate salts as catalyst, wherein thecomputational total water content of the reactants consisting ofalkoxysiloxanes and polyetherols is ≤5000 ppm by mass, advantageously≤300 ppm by mass, preferably ≤150 ppm by mass, more preferably ≤100 ppmby mass, in particular ≤50 ppm by mass, wherein the determination of theindividual water contents is performed beforehand, preferably bytitration according to Karl Fischer.

2.) Process according to embodiment 1, characterized in that thecatalyst

is a metal trifluoromethanesulfonate according to formula (I)

[CF₃SO₃ ⁻]_(x)[M]^(x+)

where M is a metal atom selected from zinc, bismuth, aluminium, iron orselected from sodium, potassium with the proviso that methanesulfonicacid is present, and x is a number up to a maximum valency of the metalatom selected for M.

3.) Process according to embodiment 1 or 2, characterized in that thecatalyst is employed in amounts of 0.01 to 1.0 percent by weight,preferably 0.07 to 0.8 percent by weight, based on the mass of thereaction matrix consisting of polyetherol and alkoxysiloxane.

4.) Process according to at least one of embodiments 1 to 3,characterized in that the polyetherol is employed in amounts ofpreferably in each case 0.8 to 2.0 OH-equivalents, particularlypreferably 0.8 to 1.3 OH-equivalents, based on every alkoxy group bondedto the silicone skeleton.

5.) Process according to at least one of embodiments 1 to 4,characterized in that the alkoxysiloxanes conform to at least one of theformulae (II) to (VI):

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 1≤n≤250and/or

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 1≤a≤60 andwhere 0<b≤10and/or

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 0≤x≤250 andwhere 1≤y≤50and/or

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 0≤x≤250 and1≤y≤50and/or

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 4≤(k+l)≤5 andl≥1.

6.) Process according to at least one of embodiments 1 to 5,characterized in that the alkoxysiloxanes are preferably compounds offormula (II) and/or formula (III).

7.) Process according to at least one of embodiments 1 to 6,characterized in that the employed polyetherols are preferably those offormula (VII)

A[-O—(CH₂—CHR′—O—)_(m)—(CH₂—CH₂—O—)_(n)—(CH₂—CH(CH₃)—O—)_(o)—Z]_(a)  (VII)

whereA is either hydrogen or an at least one carbon atom-comprising saturatedor unsaturated organic radical, preferably an at least one carbonatom-comprising organic radical of an organic starter compound forpreparing the compound, more preferably a methyl, ethyl, propyl, butyl,vinyl or allyl group,R′ is independently at each occurrence a saturated alkyl groupcomprising 2-18 carbon atoms or an aromatic radical, preferably an ethylgroup or a phenyl radical respectively,Z is hydrogen,m=from 0 to 50, preferably from 0 to 30, particularly preferably from 0to 20,n=from 0 to 250, preferably from 3 to 220, particularly preferably from5 to 200,o=from 0 to 250, preferably from 3 to 220, particularly preferably from5 to 200,a=from 1 to 8, preferably from greater than 1 to 6, particularlypreferably 1, 2, 3 or 4,with the proviso that the sum of m, n and o is equal to or greater than1.

8.) Processes according to at least one of embodiments 1 to 7,characterized in that compounds of formula (VII) comprising exclusivelyhydrogen atoms, oxygen atoms and carbon atoms are employed.

9.) Process according to at least one of embodiments 1 to 8,characterized in that the transesterification of the alkoxysiloxanes isperformed without the use of solvents.

10.) Process according to at least one of embodiments 1 to 8,characterized in that the transesterification of the alkoxysiloxanes isperformed in a solvent inert under reaction conditions, whereinpreferred solvents are toluene and/or xylenes in pure form or as anisomer mixture and wherein these solvents are preferably employed intotal amounts of 5% to 35% by weight, preferably 10% to 35% by weight,based on the mass of the reaction matrix and wherein the total watercontent of the solvents is ≤50 ppm by mass, preferably ≤25 ppm by mass,particularly preferably ≤10 ppm by mass, wherein the determination ofthe water content is performed by titration according to Karl Fischer.

11.) Process according to one of embodiments 1 to 10, characterized inthat the transesterification reaction is performed in a temperaturerange of 80° C. to 180° C. preferably 110° C. to 150° C.

12.) Process according to at least one of embodiments 1 to 11,characterized in that the transesterification reaction is performed atreduced pressure and with passing through of an inert gas.

13.) Use of the SiOC-bonded polyether siloxanes produced according to atleast one of embodiments 1 to 12 whose polyether portion is derived fromthe alkoxylation of unsaturated starter alcohols, preferably from allylalcohol, as PU foam stabilizer, defoamer and/or deaerator and also asdefoamer and/or deaerator components in paint and binder systems.

DETAILED DESCRIPTION OF THE INVENTION

The present invention accordingly provides a process for producingSiOC-bonded polyether siloxanes by transesterification ofalkoxysiloxanes with polyetherols in the presence oftrifluoromethanesulfonate as catalyst, wherein the computational totalwater content of the reactants, consisting of alkoxysiloxanes andpolyetherols, is ≤5000 ppm by mass, advantageously ≤300 ppm by mass,preferably ≤150 ppm by mass, more preferably ≤10 ppm by mass, inparticular ≤50 ppm by mass, wherein the determination of the individualwater contents is performed beforehand, preferably by titrationaccording to Karl Fischer.

The proportions of water may be determined by various methods known perse. However, Karl Fischer titration, for example according to DIN 51777,is particularly suitable.

The term “Karl Fischer titration” refers to the method of quantitativeoxidimetric determination of water developed by Karl Fischer and knownto those skilled in the art. The analysis may be performed by volumetricmeans and, for smaller water amounts (in particular ≤200 ppm by mass),preferably also by coulometric means. The titration end point isrevealed by an iodine excess which may be indicated by visual,photometric or electrometric means. All this is well known to thoseskilled in the art.

In the examples section, the water determination according to KarlFischer is described more particularly with reference to DIN 51777, DGFE-III 10 and DGF C-III 13a. The DGF standard refers to the“DGF-Einheitsmethoden” i.e. the loose-leaf publication “DeutscheEinheitsmethoden zur Untersuchung von Fetten, Fettprodukten, Tensidenund verwandten Stoffen”, 2nd edition including 22nd update.ISBN10:3804723470, wissenschaftliche Verlagsgesellschaft.

The term “computational total water content” is to be understood asmeaning that the water content of the individual components, comprisingalkoxysiloxanes and polyetherols, is captured separately for eachindividual component and subsequently summed to afford the computationaltotal water content. This water content relates to the situation beforereaction commencement which is initiated by temperature elevation andcatalyst addition.

In the context of the present invention, it is particularly preferredand thus corresponds to a particularly preferred embodiment when thetotal water content of the reactants, consisting of alkoxysiloxanes andpolyetherols, is ≤5000 ppm by mass, preferably ≤300 ppm by mass, morepreferably ≤100 ppm by mass, in particular ≤50 ppm by mass, wherein thedetermination of the water content is performed by titration accordingto Karl Fischer, in particular by coulometric Karl Fischer titration.

The advantages of the catalyst for use according to the inventioninclude that it obviates the use of acids or bases which in operationalpractice require elevated safety measures for their handling and evenfor the choice of suitable container materials. The catalyst accordingto the invention likewise obviates the otherwise customaryneutralization of acids or bases after completion of the reaction andalso avoids the cost and complexity adding filtration step for removalof the salt. In addition, the by-product hexamethylcyclotrisiloxane (D3)can be minimized or significantly reduced.

Further undesired effects arising from the use of strong acids astransesterification catalysts result from the severe dark discolorationof the products and from the subsequent equilibration thereof. Thecomparative example (example 8, cf. examples section below) elucidatesthat, while in a system consisting of anα,ω-diethoxypolydimethylsiloxane and a polyetherol in the presence of acatalytic amount of trifluoromethanesulfonic acid (0.1% by weight basedon the total weight of the reactants), quantitative conversions areachieved, the isolated final product exhibits dark brown discolorationand additionally contains considerable amounts of cyclicpolydimethylsiloxanes (D₄ and D₅). These quality deficits are in no wayacceptable on the product side.

The catalyst for use according to the invention has a less criticaltoxicological profile compared to organotin transesterificationcatalysts. Compared to the otherwise also often employedhydrolysis-sensitive titanate catalysts, triflate salts have theadvantage of hydrolytic insensitivity, i.e. zinc triflate may also beportioned, metered and transferred without inertization in an ordinaryatmosphere.

Trifluoromethanesulfonate salts are preferably suitable as catalyst forthe transesterification reaction of systems consisting ofalkoxypolysiloxane and polyetherol that are inputs for demandingapplications, for example paint additives. These additives showpractically no error tolerance in sensitive coating systems and are thussensitive indicators for process-contingent deviations from the chemicalnature of the material.

It has been found in the context of the present invention that,surprisingly, not only polyetherols derived from the alkoxylationreaction of saturated starter alcohols but for example also thosederived from the alkoxylation of unsaturated starter alcohols, forexample allyl alcohol, are suitable for the transesterificationreaction.

This finding is important especially for SiOC-bonded silicone polyethercopolymers as additives in coating systems because it allows forincorporation of terminally unsaturated groups which in turn bring abouta dispersion-stabilizing effect for example in pigment-filled paint andbinder systems. The invention accordingly further provides for the useof the SiOC-bonded polyether siloxanes produced by processes accordingto the invention whose polyether portion is derived from thealkoxylation of unsaturated starter alcohols, preferably from allylalcohol, as defoamers and/or deaerators and also as defoamer and/ordeaerator components in paint and binder systems.

Trifluoromethanesulfonate salt for use as transesterification catalystaccording to the invention allows, even under moderate conditions,virtually quantitative exchange of the alkoxy groups bonded to thesilicone skeleton for polyetherols without occurrence of side reactionssuch as equilibration or skeletal rearrangement of the employed siliconebody. High resolution ²⁹Si-NMR spectroscopy is particularly suitable fordetecting such undesired side reactions.

The reliable reproducibility of the transesterification reactionsinduced by using the catalyst according to the invention is additionallyunderscored by test series and said catalyst is thereby alreadyqualified for operational practice.

While the inventive trifluoromethanesulfonate catalyst itself featuresgood hydrolytic stability, in the transesterification reaction it ispreferable to ensure that systemic anhydrousness is adhered to verycarefully, i.e. both the employed alkoxy-comprising siloxane andemployed polyetherol and also any employed solvents are preferably to beemployed in substantially anhydrous form and/or subjected to suitabledrying processes.

The total water content of the reactants, consisting of alkoxysiloxanesand polyetherols, is ≤5000 ppm by mass, advantageously ≤300 ppm by mass,preferably ≤150 ppm by mass, more preferably ≤100 ppm by mass, inparticular ≤550 ppm by mass, wherein the determination of the watercontent is performed by titration according to Karl Fischer.

Those skilled in the art accomplish the desired systemic anhydrousnessvia commonplace processes, for example the use of commonplace dryingagents (for example sodium sulfate, calcium oxide, etc.).

In the context of the present invention, azeotropic drying and thestripping process in particular have proven useful for producing thedesired anhydrousness.

A suitable method for the drying of the employed reaction mixtures isthus preferably azeotropic drying, in which the polyetherol and/oralkoxysiloxane to be dried is admixed with a sufficient amount of a lowboiling solvent which forms with the water originating from thepolyetherol and/or alkoxysiloxane an azeotrope removable bydistillation.

A further preferred option for drying the reaction mixture employed inthe transesterification reaction may be realized via the strippingprocess, namely for example by passing an inert gas stream (preferablyfor a period of about 2 hours) through the system which is preferablyheated (for example to 140° C.) and subjected to an auxiliary vacuum(for example 1 mbar). In the context of a drying that is gentle to theproduct (avoidance of oxidative processes), preference is given tonitrogen or argon as inert gases to be employed. This strippingoperation results in a drying that is particularly intensive in thecontext of the invention and constitutes a preferred drying process. Aparticularly preferred embodiment comprises at the end of the dryingphase, while still hot, breaking the applied auxiliary vacuum by massiveapplication of an inert gas, subsequently admixing the reaction matrixwith a catalytic amount of trifluoromethanesulfonate salts, reapplyingan auxiliary vacuum and once again passing a stream of inert gas throughthe reaction matrix over (for example 5 hours) to expel the alkanoloriginating from the alkoxypolysiloxane.

The examples according to the invention underscore what is statedhereinabove. For example, the zinc triflate catalyst employed ininventive example 1 has a water content of 0.4% by weight. After atwo-hour transesterification reaction this results in quantitativeconversion being achieved and GC analysis reveals the by-producthexamethylcyclotrisiloxane D3 is present in an amount of 1.9%.

The comparative example (example 7=EP 34 38 158 A1) using zincacetylacetonate affords a product comprising a large amount of D3(17.1%). The terms “trifluoromethanesulfonate salts”, “metaltrifluoromethanesulfonates”, “triflates” and “metal triflates” are to beunderstood as being synonymous here.

It is preferable when in the transesterification reaction according tothe invention the polyetherol is employed in amounts of preferably ineach case 0.8 to 2.0 OH-equivalents, particularly preferably 0.8 to 1.3OH-equivalents, based on every alkoxy group bonded to the siliconeskeleton. This corresponds to a preferred embodiment of the invention.

In a preferred embodiment of the invention, the inventivetransesterification of the alkoxysiloxanes is performed without the useof solvents. In the context of this embodiment, pre-dried reactants inparticular are employed.

In another preferred embodiment of the process according to theinvention, the transesterification reaction is performed in a solventinert under reaction conditions. Particularly preferred solvents aretoluene and xylenes in pure form or as an isomer mixture. It ispreferable to perform the transesterification reaction in the solventwhich was previously used to perform the optional azeotropic drying ofone or more reactants or system components. To ensure the systemicanhydrousness desired according to the invention, the preferablyemployed solvents may for example also optionally be subjected to a veryeffective pre-drying for example with sodium/benzophenone and subsequentdistillation under inert gas application.

The total water content of the optional solvents should advantageouslybe ≤50 ppm by mass, preferably ≤25 ppm by mass, particularly preferably≤10 ppm by mass, wherein the determination of the water content ispreferably performed by a coulometric titration according to KarlFischer.

Solvents are preferably employed in amounts of 5% to 35% by weight,preferably 10% to 35% by weight, based on the mass of the reactionmatrix.

It is likewise possible to perform the transesterification reaction inthe absence of solvents.

At atmospheric pressure (1013.25 hPa) the transesterification reactionaccording to the invention is performed in a temperature range upwardlylimited by the boiling point of an optionally chosen solvent. It ispreferable according to the invention to choose transesterificationtemperatures between 110° C. and 150° C. This corresponds to a preferredembodiment of the invention.

Trifluoromethanesulfonate salt is preferably employed in amounts of 0.01to 1.0 percent by weight, more preferably 0.07 to 0.8 percent by weight,based on the mass of the reaction matrix consisting of polyetherol andalkoxypolysilane.

It is preferable when anhydrous trifluoromethanesulfonate salt isemployed in the context of the invention. If water-containingtrifluoromethanesulfonate salt precursor complexes are to be employedfor the process claimed in accordance with the invention, therequirement to be largely anhydrous as elucidated for the use ofpolyetherol, alkoxysiloxane and optionally solvent appliescorrespondingly, i.e. these catalysts should then preferably still bedried by suitable means (for example also by azeotropic drying) beforeuse. The presence of water of crystallization bound to thetrifluoromethanesulfonate salt does not in principle inhibit theefficacy thereof according to the invention but does have the effectthat the transesterification reactions catalysed therewith are retarded.

In the context of a preferred transesterification reaction whichadvantageously proceeds rapidly and completely,trifluoromethanesulfonate salt according to the invention shouldpreferably have water contents of less than 7.5% by weight, preferablyless than 5% by weight and very particularly preferably ≤2% by weight.

In preferably employable processes the catalyst is a metaltrifluoromethanesulfonate according to formula (1)

[CF₃SO₃ ⁻]_(x)[M]^(x+)   (I)

where M is a metal atom selected from zinc, bismuth, aluminium, iron orselected from sodium, potassium with the proviso that methanesulfonicacid is present, and x is a number up to a maximum valency of the metalatom selected for M.

Alkoxypolysiloxanes preferably employable according to the invention areselected from the compounds of formula (II) to formula (VI), wherein useof the alkoxypolysiloxanes according to formula (II) and/or formula(III) is particularly preferred.

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 1≤n≤250

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 1≤a≤60 andwhere 0<b≤10

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 0≤x≤250 andwhere 1≤y≤50

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 0≤x≤250 and1≤y≤50

where R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to 10carbon atoms,R=alkyl radical comprising 1 to 8 carbon atoms andwhere 4≤(k+l)≤5 andl≥1.

The polyetherols employable according to the invention are preferablythose of formula (VII)

A[-O—(CH₂—CHR′—O—)_(m)—(CH₂—CH₂—O—)_(n)—(CH₂—CH(CH₃)—O—)_(o)—Z]_(a)  (VII)

whereA is hydrogen or an at least one carbon atom-comprising saturated orunsaturated organic radical, preferably an at least one carbonatom-comprising organic radical of an organic starter compound forpreparing the compound, particularly preferably a methyl, ethyl, propyl,butyl, vinyl or allyl group,R′ is independently at each occurrence a saturated alkyl groupcomprising 2-18 carbon atoms or an aromatic radical, preferably an ethylgroup or a phenyl radical respectively,Z is hydrogen,m=from 0 to 50, preferably from 0 to 30, particularly preferably from 0to 20,n=from 0 to 250, preferably from 3 to 220, particularly preferably from5 to 200,o=from 0 to 250, preferably from 3 to 220, particularly preferably from5 to 200,a=from 1 to 8, preferably from greater than 1 to 6, particularlypreferably 1, 2, 3 or 4,with the proviso that the sum of m, n and o is equal to or greater than1.

It is preferable to employ compounds of formula (VII) comprisingexclusively hydrogen atoms, oxygen atoms and carbon atoms.

The index values recited here, and the value ranges of the indicesspecified may be understood to mean averages (weight averages) of thepossible statistical distribution of the structures actually presentand/or the mixtures thereof. This also applies to structural formulaeexactly reproduced per se as such, for example to formula (VII).

The units labelled m, n, and o may either be statistically mixed or elsemay form a blockwise arrangement in the chain. Statistical distributionsmay have a blockwise structure with any number of blocks and anysequence or be subject to a randomized distribution; they may also havean alternating structure or else form a gradient along the chain; inparticular, they can also form any mixed forms thereof in which groupsof different distributions may follow one another. Specific embodimentsmay lead to restrictions to the statistical distributions as a result ofthe embodiment. There is no change in the statistical distribution forall regions unaffected by the restriction.

In the context of the present invention, radical A is preferably to beunderstood as meaning radicals of substances forming the start of theto-be-produced compound of formulae (V) which is obtained by addition ofalkylene oxides. The starter compound is preferably selected from thegroup of alcohols, polyetherols and phenols. It is preferable to use asthe starter compound containing the group A a mono- or polyfunctionalpolyether alcohol and/or a mono- or polyfunctional alcohol or anydesired mixtures thereof. If a plurality of starter compounds A has beenused as a mixture, the index a may also be subject to a statisticaldistribution. Z may in addition also be the radical of a startercompound Z—OH.

Monomers used with preference in the alkoxylation reaction are ethyleneoxide, propylene oxide, butylene oxide and/or styrene oxide and also anydesired mixtures of these epoxides. The different monomers may be usedin pure form or as a mixture. A further epoxide can also be meteredcontinuously over time into an epoxide already present in the reactionmixture, so as to give rise to an increasing concentration gradient ofthe epoxide added continuously. The polyoxyalkylenes formed are thussubject to a statistical distribution in the end product, restrictionsbeing determinable via the metered addition. In this case of thecontinuous addition of a further epoxide to an epoxide already presentin the reaction mixture, a structure gradient along the length of thechain is to be expected. The correlations between metered addition andproduct structure are known to those skilled in the art.

It is preferable to employ in the process according to the inventioncompounds from compound class II having a weight-average molar mass of76 to 10 000 g/mol, preferably of 100 to 8000 g/mol and particularlypreferably of 200 to 6000 g/mol.

Compounds from compound class II that may be employed are preferablycompounds derived from a compound of formula (VIII)

A[-OH]a  (VIII)

wherein the radical A derives from compounds selected from the groupconsisting of mono- and polyfunctional monomers, oligomers and polymericalcohols, phenols, carbohydrates and carbohydrate derivatives, whereinparticular preference is given to using compounds of formula (VI) wherethe radical A derives from one or more alcohols from the group ofbutanol, 1-hexenol, octanol, dodecanol, stearyl alcohol,vinyloxybutanol, 2-ethylhexanol, cyclohexanol, benzyl alcohol, ethyleneglycol, propylene glycol, di-, tri- and polyethylene glycol,1,2-propylene glycol, di- and polypropylene glycol, 1,4-butanediol,1,6-hexanediol, trimethylolpropane, glycerol, pentaerythritol, sorbitol,allyl alcohol, vinyl alcohol or from hydroxyl group-bearing compoundsbased on natural products.

Particular preference is given to using compounds from compound class IIthat are liquid at a pressure of 101 325 Pa and a temperature of 23° C.Among these, very particular preference is given to butyl diglycol,dipropylene glycol and propylene glycol.

Compounds of formula (III) employable in accordance with the inventionas polyetherols and processes for the production thereof are describedfor example in EP 0075703, U.S. Pat. No. 3,775,452 and EP 1031603.Suitable processes utilize, for example, basic catalysts, for examplealkali metal hydroxides and alkali metal methoxides. The use of KOH isparticularly widespread and has been known for many years. Suchprocesses typically comprise reacting a hydroxy-functional starter,generally of low molecular weight, i.e. having a molecular weight below200 g/mol, such as butanol, allyl alcohol, propylene glycol or glycerol,with an alkylene oxide such as ethylene oxide, propylene oxide, butyleneoxide or a mixture of different alkylene oxides in the presence of thealkaline catalyst to afford a polyoxyalkylene polyether. The stronglyalkaline reaction conditions in this so-called living polymerizationpromote various side reactions. The compounds of formulae (II) may alsobe produced by double metal cyanide catalysis. Polyethers produced bydouble metal cyanide catalysis generally have a particularly low contentof unsaturated end groups of less than or equal to 0.02 milliequivalentsper gram of polyether compound (meq/g), preferably less than or equal to0.015 meq/g, particularly preferably less than or equal to 0.01 meq/g(test method ASTM D2849-69), contain distinctly fewer monools andgenerally have a low polydispersity of less than 1.5. The polydispersity(PD) may be determined by a method known per se to those skilled in theart by determining by gel permeation chromatography (GPC) both thenumber-average molecular weight (Mn) and the weight-average molecularweight (Mw). The polydispersity is defined by PD=Mw/Mn. The productionof such polyethers is described in U.S. Pat. No. 5,158,922 and EP-A0654302 for example.

Irrespective of the production route, compounds of formula (VII)preferably having a polydispersity Mw/Mn of 1.0 to 1.5, by preferencehaving a polydispersity of 1.0 to 1.3, are preferentially suitable.

Depending on the alkylene oxide terminus, the polyetherols for useaccording to the invention may have a primary or secondary OH function.In terms of the aspect of the hydrolytic resistance of the obtainedSiOC-bonded polyether siloxanes achieved later, the use of polyetherolscomprising a secondary alcohol function is preferred in the context ofthe inventive teaching.

The invention further provides for the use of the SiOC-bonded polyethersiloxanes whose polyether portion is derived from the alkoxylation ofunsaturated starter alcohols, preferably from allyl alcohol, butanol ordipropylene glycol, as PU foam stabilizer, defoamer and/or deaerator andalso as defoamer and/or deaerator component in paint and binder systems.

The examples which follow are provided merely to elucidate thisinvention to those skilled in the art and do not constitute anylimitation of the claimed process whatsoever. The inventivedetermination of the water contents is performed in principle with theKarl Fischer method based on DIN 51777, DGF E-IIII 10 and DGF C-III 13aand in particular as described in detail in the examples section.²⁹Si-NMR spectroscopy was used in all examples to monitor the progressof the reaction with regard to completeness of the transesterificationreaction.

EXAMPLES

In the inventive examples, before addition of the zinc acetylacetonatethe computational total water content of the reactants consisting ofalkoxysiloxanes and polyetherols was in each case below 300 ppm by mass,wherein the determination of the individual water contents was performedbeforehand by titration according to Karl Fischer.

Water determination according to Karl Fischer

Based on DIN 51777, DGF E-III 10 and DGF C-III 13a

The water content is the amount of water calculated from the iodineconsumption by the following method. The sample is titrated in thepresence of methanol with a solution containing sulfur dioxide andiodine. Since sulfur dioxide and iodine react to afford equivalentamounts of sulfur trioxide and hydrogen iodide only in the presence ofwater, the iodine consumption can be used to calculate the water contentin weight percent.

J ₂+SO₂+H₂O=2HJ+SO₃

Unless otherwise stated, all reagents have the purity grade AR.

Karl Fischer solution: Hydranal Composite 5, Riedel de Haen; 34805

Methanol AR;

Chloroform AR;

Karl Fischer titrator; (for example Metrohm; KF-Titrino 701 or 758)

Titration stand: Metrohm.

Switching unit 20 ml with ceramic cock

Magnetic stirrer bar, 25 mm; for example Metrohm.

Double Pt electrode; Metrohm.

Analytical balance; for example Sartorius AC210S

Drying tube with activated molecular sieves; Metrohm.

The molecular sieves should be replaced for each change of the titrationsolution. Regeneration of the molecular sieves is performed in a dryingcabinet at 180° C.-240° C. over 48 hours.

Procedure

The sample is to be homogenized by thorough stirring.

In a titration vessel, methanol or methanol/chloroform (1:1) areinitially charged (fill height ⅓ to ¼ of vessel) and titrated tocompletion with composite 5. A suitable weight of the sample fordetermination is weighed into the titration vessel by differentialweighing via an analytical balance directly or with a single-usesyringe. The titration is performed up to the electrometric endpoint.

Evaluation

$\frac{V \times F}{10 \times E} = {{water}\mspace{14mu} {{content}\mspace{14mu}\lbrack {\% \mspace{14mu} {by}\mspace{14mu} {weight}} \rbrack}}$

V=consumption of composite 5 solution (ml)F=factor of composite 5 solutionE=sample weight (g)

In the context of the present invention the ²⁹Si-NMR samples aremeasured at 22° C., dissolved in CDCl₃ and against tetramethylsilane(TMS) as the external standard [d(²⁹Si)=0.0 ppm] at a measurementfrequency of 79.49 MHz in a Bruker Avance III spectrometer equipped witha 287430 sample head with a 10 mm slot width.

The GPCs (gel permeation chromatography) are recorded using THF as themobile phase on an SDV 1000/10000A column combination, length 65 cm, ID0.80, at a temperature of 30° C. using a SECcurity² GPC system 1260 (PSSPolymer Standards Service GmbH).

The gas chromatograms are recorded on an Agilent Technologies GC 7890BGC instrument fitted with an HP-1 column, 30 m×0.32 mm ID×0.25 μm dF(Agilent Technologies no. 19091Z-413E), using hydrogen as the carriergas and the following parameters:

Detector: FID; 310° C.

Injector: split; 290° C.Mode: constant flow 2 mL/minTemperature program: 60° C. at 8° C./min and 150° C. at 40° C./min and300° C. for 10 min.

The gas-chromatographically determined total cycle content defined asthe sum of the D₄, D₅ and D₆ contents based on the siloxane matrix anddetermined after derivatization of the branched acetoxy-bearingsiloxanes to the corresponding branched, isopropoxy-group-bearingsiloxanes is used as an indicator for achievement of the equilibriumstate. Derivatization into the branched, isopropoxy-group-bearingsiloxanes is intentionally chosen to prevent a thermally inducedretro-cleavage reaction of the branched acetoxy-group-bearing siloxaneswhich may optionally take place under the conditions of analysis of gaschromatography (regarding the retro-cleavage reaction see inter alia J.Pola et al., Collect. Czech. Chem. Commun. 1974, 39(5), 1169-1176 andalso W. Simmler, Houben-Weyl, Methods of Organic Chemistry, Vol. VI/2,4th Edition, O—Metal Derivates of Organic Hydroxy Compounds p. 162 ﬀ)).

Example 1 (Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 60.0 g (0.05 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equivalent amount(based on ethoxy groups) of a butanol-started polyetherol (propyleneoxide proportion of 100%) having a molar mass of 1870 g/mol (molar massdetermined according to OH number) with stirring and application of anoil pump vacuum of 1 mbar were heated to 140° C. for 2 hours, an argonstream of approximately 3 l/hour being passed through the reactantmixture using the gas introduction tube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.17 g of solid zinc triflate (water content in the catalyst was0.4% by weight) was introduced with inertization into the thus pre-driedheated reaction matrix. The addition was performed at 150° C. and thetemperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reaction mixturefor a period of 5 hours.

After cooling of the reaction batch and renewed breaking of theauxiliary vacuum by argon introduction, a slightly cloudy, SiOC-bondedpolyether siloxane was isolated with quantitative alkoxy conversion(²⁹Si-NMR spectroscopy).

Corresponding GC analyses of the distillate were performed and thefollowing values determined for D3, D4, D5. D6 and ethanol.

GC of the distillate % D3 % D4 % D5 % D6 % Ethanol 1.9 23.7 37.3 4.632.5

Example 2 (Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 100.0 g (0.103 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equivalent amount(based on ethoxy groups) of an allyl alcohol-started polyetherol(propylene oxide proportion of 100%) having a molar mass of 501 g/mol(molar mass determined according to OH number) with stirring andapplication of an oil pump vacuum of 1 mbar were heated to 130° C. for 2hours, an argon stream of approximately 3 l/hour being passed throughthe reactant mixture using the gas introduction tube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.14 g of solid zinc triflate (water content in the catalyst was2.0% by weight) was introduced with inertization into the thus pre-driedheated reaction matrix. The addition was performed at 130° C. and thetemperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reaction mixturefor a period of 5 hours.

After cooling of the reaction batch and renewed breaking of theauxiliary vacuum by argon introduction, a slightly cloudy, SiOC-bondedpolyether siloxane was isolated with an alkoxy conversion determined by²⁹Si-NMR spectroscopy of 94%.

Example 3 (Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 100.0 g (0.103 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equivalent amount(based on ethoxy groups) of allyl alcohol-started polyetherol (ethyleneoxide proportion of 100%) having a molar mass of 387 g/mol (molar massdetermined according to OH number) with stirring and application of anoil pump vacuum of 1 mbar were heated to 140° C. for 2 hours, an argonstream of approximately 3 l/hour being passed through the reactantmixture using the gas introduction tube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.13 g of solid zinc triflate (water content in the catalyst was2.0%) was introduced with inertization into the thus pre-dried heatedreaction matrix. The addition was performed at 140° C. and thetemperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reaction mixturefor a period of 5 hours.

After cooling of the reaction batch and renewed breaking of theauxiliary vacuum by argon introduction, a slightly cloudy, slightlyyellow SiOC-bonded polyether siloxane was isolated with an alkoxyconversion determined by ²⁹Si-NMR spectroscopy of 99%.

Example 4 (Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 60.0 g (0.065 mol) of a singly branchedtriethoxypolydimethylsiloxane together with an equimolar amount (basedon ethoxy groups) of an allyl alcohol-started polyetherol (propyleneoxide proportion of 800%, ethylene oxide proportion of 20%) having amolar mass of 500 g/mol (molar mass determined according to OH number)with stirring and application of an oil pump vacuum of 1 mbar wereheated to 140° C. for 2 hours, an argon stream of approximately 3 l/hourbeing passed through the reactant mixture using the gas introductiontube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.14 g (0.09% by weight) of solid zinc triflate (water content inthe catalyst was 2.0%) was introduced with inertization into the thuspre-dried heated reaction matrix. The addition was performed at 140° C.and the temperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reaction mixturefor a period of 8 hours.

After cooling of the reaction batch and renewed breaking of theauxiliary vacuum by argon introduction, a slightly cloudy, slightlyyellow SiOC-bonded polyether siloxane having the desired targetstructure was isolated with an alkoxy conversion of 990%. Conversion wasdetermined by ²⁹Si-NMR spectroscopy.

Example 5 (Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 60.0 g (0.05 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equivalent amount(based on ethoxy groups) of a butanol-started polyetherol (propyleneoxide proportion of 100%) having a molar mass of 1870 g/mol (molar massdetermined according to OH number) with stirring and application of anoil pump vacuum of 1 mbar were heated to 140° C. for 2 hours, an argonstream of approximately 3 l/hour being passed through the reactantmixture using the gas introduction tube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.30 g of solid sodium triflate and 0.15 g of methanesulfonic acidwere introduced with inertization into the thus pre-dried heatedreaction matrix. The addition was performed at 140-150° C. and thetemperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reaction mixturefor a period of 5 hours.

After cooling of the reaction batch and renewed breaking of theauxiliary vacuum by argon introduction, a virtually clear, SiOC-bondedpolyether siloxane was isolated at quantitative alkoxy conversion(29Si-NMR spectroscopy).

Example 6 (Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 60.0 g (0.05 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equivalent amount(based on ethoxy groups) of a butanol-started polyetherol (polypropyleneoxide proportion of 100%) having a molar mass of 1870 g/mol (molar massdetermined according to OH number) with stirring and application of anoil pump vacuum of 1 mbar were heated to 140° C. for 2 hours, an argonstream of approximately 3 l/hour being passed through the reactantmixture using the gas introduction tube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.30 g of solid potassium triflate and 0.15 g of methanesulfonicacid were introduced with inertization into the thus pre-dried heatedreaction matrix. The addition was performed at 140-150° C. and thetemperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reaction mixturefor a period of 5 hours.

After cooling of the reaction batch and renewed breaking of theauxiliary vacuum by argon introduction, virtually clear, SiOC-bondedpolyether siloxane was isolated at quantitative alkoxy conversion(29Si-NMR spectroscopy).

Example 7 (Non-Inventive)

Similarly to example 2, in a 500 ml four-necked round-bottom flaskhaving a KPG stirrer, internal thermometer, gas introduction tube andfitted with a distillation bridge, 100.0 g (0.103 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equivalent amount(based on ethoxy groups) of an allyl alcohol-started polyetherol(polypropylene oxide proportion of 100%) having a molar mass of 501g/mol (molar mass determined according to OH number, water content was0.2%) were initially charged and with stirring heated to 130° C.

As soon as the reaction temperature was attained, 0.14 g of solid zincacetylacetonate (water content 2.0%) was introduced and with stirringand application of an oil pump vacuum of 1 mbar the reaction mixture washeated to 130° C. for 5 hours. The temperature was kept constant.

An argon stream of approximately 3 l/hour was passed through thereaction mixture using the gas introduction tube. After cooling of thereaction batch and renewed breaking of the auxiliary vacuum by argonintroduction, virtually clear, SiOC-bonded polyether siloxane wasisolated at quantitative alkoxy conversion (29Si-NMR spectroscopy).

Corresponding GC analyses of the distillate were performed and thefollowing values determined for D3, D4, D5, D6 and ethanol.

GC of the distillate % D3 % D4 % D5 % D6 % Ethanol 17.1 29.7 10.4 11.231.6

Example 8 (Non-Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 142.1 g (0.119 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equimolar amount(based on ethoxy groups) of a butanol-started polyetherol (80% propyleneoxide proportion, 20% ethylene oxide proportion) having a molar mass of484 g/mol (molar mass determined according to OH number) with stirringand application of an oil pump vacuum of 1 mbar were heated to 10° C.for 2 hours, an argon stream of approximately 3 l/hour being passedthrough the reactant mixture using the gas introduction tube.

The mixture was allowed to cool to 100° C. and the auxiliary vacuum wasbroken by application of a massive argon stream andtrifluoromethanesulfonic acid (0.15 ml=0.1% by weight) was added withinertization using a Hamilton syringe into the thus pre-dried heatedreaction matrix.

At an internal temperature of 100° C. and with constant stirring, onceagain an auxiliary vacuum of 250 mbar was applied and an argon stream ofapproximately 3 l/hour was passed through the reaction mixture for aperiod of 9 hours.

To neutralize the trifluoromethanesulfonic acid, 1.88 g of Na₂CO₃.H₂Oand 3.5 g of NaHCO₃ were added with stirring. The mixture was allowed toreact for 2 hours, the salts were removed by filtration and the filtratewas distilled for 2 hours at 130° C. and a pressure of 1 mbar to removecyclic siloxanes (D₄/D₅).

A clear, but brown-black discoloured, material exhibiting a quantitativealkoxy conversion according to ²⁹Si-NMR spectroscopy was isolated.

Example 9 (Non-Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 100.0 g (0.103 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equimolar amount(based on ethoxy groups) of a butanol-started polyetherol (propyleneoxide proportion of 100%) having a molar mass of 1870 g/mol (molar massdetermined according to OH number) with stirring and application of anoil pump vacuum of 1 mbar were heated to 140° C. for 2 hours, an argonstream of approximately 3 l/hour being passed through the reactantmixture using the gas introduction tube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.48 g of titanium(IV) butoxide (Fluka) was introduced withinertization into the thus pre-dried heated reaction matrix. Theaddition was performed at 140° C. and the temperature was kept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reactionmixture. After a reaction time of 5 hours, a heterogeneous biphasicproduct was obtained and analysis was therefore eschewed.

Example 10 (Non-Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 100.0 g (0.103 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equimolar amount(based on ethoxy groups) of a butanol-started polyetherol (propyleneoxide proportion of 80%, ethylene oxide proportion of 20%) having amolar mass of 484 g/mol (molar mass determined according to OH number)with stirring and application of an oil pump vacuum of 1 mbar wereheated to 140° C. for 2 hours, an argon stream of approximately 3 l/hourbeing passed through the reactant mixture using the gas introductiontube.

The auxiliary vacuum was broken by application of a massive argon streamand 0.199 g of solid zirconium(IV) acetvlacetonate (Sigma-Aldrich) wasintroduced with inertization into the thus pre-dried heated reactionmatrix. The addition was performed at 140° C. and the temperature waskept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reactionmixture. After a reaction time of 5 hours, a heterogeneous biphasicproduct was obtained and analysis was therefore eschewed.

Example 11 (Non-Inventive)

In a 500 ml four-necked round-bottom flask having a KPG stirrer,internal thermometer, gas introduction tube and fitted with adistillation bridge, 100.0 g (0.103 mol) of anα,ω-diethoxypolydimethylsiloxane together with an equimolar amount(based on ethoxy groups) of a butanol-started polyetherol (propyleneoxide proportion of 80%, ethylene oxide proportion of 20%0) having amolar mass of 484 g/mol (molar mass determined according to OH number)with stirring and application of an oil pump vacuum of 1 mbar wereheated to 130° C. for 2 hours, an argon stream of approximately 3 l/hourbeing passed through the reactant mixture using the gas introductiontube.

The auxiliary vacuum was broken by application of a massive argon streamand 3.99 g of zirconium(IV) acetylacetonate solution (5% in THF) wasintroduced with inertization into the thus pre-dried heated reactionmatrix. The addition was performed at 130° C. and the temperature waskept constant.

Once again, an auxiliary vacuum of 1 mbar was applied and an argonstream of approximately 3 l/hour was passed through the reactionmixture. After a reaction time of 5 hours, a heterogeneous biphasicproduct was obtained and analysis was therefore eschewed.

1. A process for producing a SiOC-bonded polyether siloxane, comprising:transesterifying an alkoxysiloxane with a polyetherol in the presence ofa trifluoromethanesulfonate salt as a catalyst, wherein a computationaltotal water content of reactants consisting of the alkoxysiloxane andthe polyetherol is ≤5000 ppm by mass, wherein determination of anindividual water content is performed before the transesterifying. 2.The process according to claim 1, wherein the catalyst is a metaltrifluoromethanesulfonate according to formula (I):[CF₃SO₃ ⁻]_(x)[M]^(x+)  formula (I), wherein M is a metal atom selectedfrom the group consisting of zinc, bismuth, aluminium, and iron, orselected from the group consisting of sodium and potassium, with theproviso that methanesulfonic acid is present, and x is a number up to amaximum valency of the metal atom selected for M.
 3. The processaccording to claim 1, wherein the catalyst is employed in an amount of0.01 to 1.0 percent by weight based on a mass of a reaction matrixconsisting of the polyetherol and the alkoxysiloxane.
 4. The processaccording to claim 1, wherein the polyetherol is employed in an amountof in each case 0.8 to 2.0 OH-equivalents, based on every alkoxy groupbonded to a silicone skeleton of the alkylsiloxane.
 5. The processaccording to claim 1, wherein the alkoxysiloxane conforms to at leastone of formulae (II) to (VI):

wherein R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to10 carbon atoms, R=alkyl radical comprising 1 to 8 carbon atoms, andwherein 1≤n≤250, and/or

wherein R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to10 carbon atoms, R=alkyl radical comprising 1 to 8 carbon atoms, wherein1≤a≤60, and wherein 0<b≤10, and/or

wherein R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to10 carbon atoms, R=alkyl radical comprising 1 to 8 carbon atoms, wherein0≤x≤250, and wherein 1≤y≤50, and/or

wherein R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to10 carbon atoms, R=alkyl radical comprising 1 to 8 carbon atoms, wherein0≤x≤5250, and 1≤y≤50, and/or

wherein R¹=alkyl and/or aralkyl and/or aromatic radical comprising 1 to10 carbon atoms, R=alkyl radical comprising 1 to 8 carbon atoms, wherein4≤(k+l)≤5, and l≥1.
 6. The process according to claim 5, wherein thealkoxysiloxane is at least one of formula (II) and/or formula (III). 7.The process according to claim 1, wherein the polyetherol is of formula(VII):A[-O—(CH₂—CHR′—O—)_(m)—(CH₂—CH₂—O—)_(n)—(CH₂—CH(CH₃)—O—)_(o)—Z]_(a)  formula(VII) wherein A is either hydrogen or at least one carbonatom-comprising saturated or unsaturated organic radical, R′ isindependently at each occurrence a saturated alkyl group comprising 2-18carbon atoms or an aromatic radical, Z is hydrogen, m=from 0 to 50,n=from 0 to 250, o=from 0 to 250, and a=from 1 to 8, with the provisothat a sum of m, n, and o is equal to or greater than
 1. 8. The processaccording to claim 7, wherein the polyetherol of formula (VII) consistsof hydrogen atoms, oxygen atoms, and carbon atoms.
 9. The processaccording to claim 1, wherein the transesterifying of the alkoxysiloxaneis performed without a use of solvents.
 10. The process according toclaim 1, wherein the transesterifying of the alkoxysiloxane is performedin a solvent inert under reaction conditions, wherein a total watercontent of the solvent is ≤50 ppm by mass, and wherein the determinationof the total water content of solvent is determined by Karl Fischertitration.
 11. The process according to claim 1, wherein thetransesterifying is performed in a temperature range of 80° C. to 180°C.
 12. The process according to claim 1, wherein the transesterifying isperformed at reduced pressure and with passing through of an inert gas.13. A product, comprising: the SiOC-bonded polyether siloxane producedaccording to claim 1, whose polyether portion is derived fromalkoxylation of an unsaturated starter alcohol, as PU foam stabilizer,defoamer and/or deaerator and also as defoamer and/or deaeratorcomponents in paint and binder systems.
 14. The process according toclaim 1, wherein the computational total water content of the reactantsconsisting of the alkoxysiloxane and the polyetherol is ≤50 ppm by mass,and wherein the determination of the individual water content isperformed beforehand by Karl Fischer titration.
 15. The processaccording to claim 3, wherein the catalyst is employed in an amount of0.07 to 0.8 percent by weight, based on the mass of the reaction matrix.16. The process according to claim 4, wherein the polyetherol isemployed in an amount of in each case 0.8 to 1.3 OH-equivalents, basedon every alkoxy group bonded to the silicone skeleton.
 17. The processaccording to claim 7, wherein A is at least one carbon atom-comprisingorganic radical of an organic starter compound for preparing thepolyetherol, selected from the group consisting of a methyl, ethyl,propyl, butyl, vinyl, and allyl group, R′ is independently at eachoccurrence an ethyl group or a phenyl radical, m=from 0 to 20, n=from 5to 200, o=from 5 to 200, and a=from 1, 2, 3 or
 4. 18. The processaccording to claim 10, wherein the solvent is at least one selected fromthe group consisting of toluene and xylene, in pure form or as an isomermixture, wherein the solvent is employed in total amounts of 5% to 35%by weight based on the mass of the reaction matrix, and wherein thetotal water content of the solvent is ≤10 ppm by mass.
 19. The processaccording to claim 11, wherein the transesterifying is performed in atemperature range of 110° C. to 150° C.
 20. The product according toclaim 13, wherein the unsaturated starter alcohol is allyl alcohol.